1. Food
• The major limiting factor to human population
growth
• Depends on environment and socio-political
issues
• Right now distribution is the main problem
• If the human population continues to grow,
quantity will be the problem
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2. Earth as an Apple
http://www.farmland.org/Flash/appleEarth.html
Where does our food come from?
• Land crops and livestock!
– Only 14 species of plants
• Cash crops
• Subsistence crops
• Top food crops:
– Wheat, rice, maize, potatoes
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3. How much food do people need?
• 2600 calories/day
• If they don’t get this:
•
undernourishment
If they don’t get specific
nutrients:
malnourishment
– Marasmus, kwashiorkor,
chronic hunger
• On the flip side of the
coin: obesity
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4. Nutrition
•Undernourishment =
•too few calories
•(especially developing
world)
•Overnutrition =
•too many calories
•(especially developed
world)
•Malnutrition = lack of
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nutritional requirements
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Figure 9.2

5. Percentage of population affected by
undernutrition by country, according to
United Nations statistics
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6. Global food security
•The world still has 800 million hungry people,
largely due to inadequate distribution.
•Global food security is a goal of scientists and
policymakers worldwide.
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7. HOW TO FEED THE WORLD
• http://www.youtube.co
m/watch?v=QloMOOGbbE
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8. The best ways
• “Give a man a fish and
•
you feed him for a day.
Teach a man to fish and
you feed him for a
lifetime.” –Lao Tzu
Create systems where
food is grown and
distributed locally
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9. Agriculture
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10. Grain production
(millions of tons)
2,000
1,500
1,000
500
0
1950
1960
1970
1980
1990
2000
2010
Year
Total World Grain Production
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11. Per capita grain production
(kilograms per person)
400
350
300
250
200
150
1950
1960
1970
1980
1990
2000
2010
Year
World Grain Production per Capita
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12. Calories per day per person
3,700
Developed countries
3,500
3,300
3,100
2,900
World
2,700
Developing
countries
2,500
2,300
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Year3
Unit
2030
2010
2000
1990
1980
1970
1960
2,100
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13. Natural Capital
Figure 14-3 Croplands
Page 276
Ecological
Croplands
Economic
Services
Economic Services
Services
Ecological Services
•Help maintain water flow and
• Helpinfiltration water
soil maintain
•Food crops
• Food crops
flow and soil infiltration
• •Provide partial erosion protection
Provide partial erosion
protection
•Can build soil organic matter
• Can build soil organic
matter
• Fiber crops
•Fiber crops
• Crop genetic
resources
•Crop genetic
• Jobs
resources
•Store atmospheric carbon
• Store atmospheric
carbon
•Provide wildlife habitat for some
species
• Provide wildlife habitat
for some species
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•Jobs
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14. Biodiversity Loss
Soil
Loss and degradation of habitat from
clearing grasslands and forests and
draining wetland
Erosion
Loss of fertility
Fish kills from pesticide runoff
Salinization
Killing of wild predators to protect
livestock
Waterlogging
Loss of genetic diversity from
replacing thousands of wild crop
strains with a few monoculture strains
Desertification
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15. Air Pollution
Water
Greenhouse gas emissions from fossil
Fuel issue
Other air pollutants from fossil fuel use
Pollution from pesticide sprays
Water waste
Aquifer depletion
Increased runoff and
Overfertilization of lakes
flooding from land cleared and slow-moving rivers
to grow crops
from runoff of nitrates
and phosphates from
Sediment pollution from
fertilizers, livestock
erosion
wastes, and food
processing wastes
Fish kills from pesticide
runoff
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Surface and groundwater
pollution from pesticides
and fertilizers
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16. 4%
2%
6%
5%
Crops
Livestock
Food processing
Food distribution and preparation
17% of total
commercial
energy use
Food production
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17. Producing and eating meat
• Land use issues
– More land needed
• More land needed for grazing than grain production
• Acre of grain for human consumption feeds more than
an acre used for grazing
• Land needed to grow forage AND raise animals:
Housing, food storage and waste disposal
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18. Producing and eating meat
• Energy issues
– Eating at a lower trophic level
• More solar energy available to humans, less lost through
trophic transfer
– Storage of grain less energetically expensive than
processing and storing meat
• Transport, slaughter and refrigeration
– Energy costs associated with meat production
• Producing grain for livestock
– Fertilizers, irrigation, pesticides, farm machinery
• Animal waste management
– Pumping, treatment, transport, disposal
• Animal care and round up of free range livestock
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19. Eating less meat: Pro and
Con
• Advantages
– Reduced risk of disease
• Cholesterol
• Disadvantages
– Meat an excellent source
of protein
• Essential amino acids
– Clogged arteries
– Hypertension
– Heart disease
– Reduced chemical
exposure
• Hormones
• Steroids
• Antibiotics
• Pesticides (Biomag!)
– Reduced exposure to
disease
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– Rice and Beans!
• Difficult to get enough
protein without meat
– Nutritional deficiencies
• Kwashikor: Protein
• Blindness: Vit. A
• Pollegra: Vit. B
• Anemia: Iron
• Inadequate essential fats
balance
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20. How do we address world hunger?
• Policy and behavioral
•
•
•
•
changes
Eat lower on the food
chain?
Modify food
distribution
Improve infrastructure
Economic policies
– End subsidies
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21. To feed the world….
• Conservation of matter
– Available resources limit agricultural production
– Nutrients used by plants
• Nitrates: Protein and DNA
• Phosphates: DNA, RNA, ATP
– Soil degraded as nutrients removed by harvest
• Conservation of Energy
– Trophic level energy loss
• Vegetarian vs Carnivorous diets
• Green revolution
–
–
–
–
Increase yield per acre
Monoculture
Intensive tillage = soil erosion
Requires
• Energy: Emissions and oil
• Fertilizers and pesticides: Toxic pollution, soil salinization
• Irrigation: Water rights and usage
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